Project Summary/Abstract Traumatic brain injury (TBI) is a public health crisis for children in the US and worldwide. There are no proven therapies to treat TBI, and evidenced-based guidelines have been developed over the past 2 decades to guide best current practices. Yet, implementation strategies are lacking. In prior work, we found that adherence to the TBI guidelines was associated with 6% better outcomes in 5 leading U.S. academic centers. However, TBI guideline adherence remains low and the guidelines have limitations related to recommendation applicability across health care systems and across countries. In response, we developed and pilot tested an innovative multilevel Pediatric Guideline Adherence and Outcomes (PEGASUS) program to increase TBI guideline adherence. Preliminary data show that barriers to TBI guideline adherence are remediable and TBI guideline based intensive care benefits outcomes. This proposal is a collaboration between U.S. and Argentine TBI clinical investigators dedicated to understanding TBI guideline adherence. The overarching aim of this proposal is guided by the Theoretical Domain Framework. We propose to conduct a pragmatic cluster randomized controlled trial of the PEGASUS program (intervention) and to improve TBI guideline adherence (main outcome) in severe pediatric TBI across six Argentine study sites. Using mixed-methods, we propose 3 Specific Aims: 1) Determine the relationship between PEGASUS program implementation and TBI guideline adherence (Aim 1a), and assess system, provider, patient, implementation and guideline factors associated with TBI guideline adherence (Aim 1b), 2) Create a value stream map that readily identifies value added process of care associated with TBI guideline adherence, and 3) Use computer simulation to develop and disseminate a real world best practices blueprint for TBI guideline adherence. This is a necessary advance and a step towards implementing guideline-based TBI care for children who suffer from TBI.